ACUTE TOXICITY OF SOME INSECTICIDES ON HONEYBEE, Apis mellifera L.

Document Type : Original Article

Authors

1 1. Nat. Res. Dept., Inst. Asian Studies and Res., Zagazig Univ., Egypt

2 2. Plant. Prot. Res. Inst., ARC, Giza, Egypt

3 3. Plant. Prot. Dept., Fac. Agric. Zagazig Univ., Egypt

Abstract

This work was conducted to evaluate the toxicity of some insecticides against honeybee workers under laboratory conditions. Among the tested insecticides, Deltamethrin was the most toxic compound followed by Methomyl while Chlorpyrifos was the least one followed by Profenfos after 24, 48, and 72 hr., of topical exposure. The results indicated that there was negative relationship between the time post treatment and lechal concentration (LC50) values of all the tested insecticides. The LD50 values were 9.5, 10.45, 3.68, 18.33 and 12.55 μg/bee for Methomyl, Cyhalothrin, Deltamethrin, Chlorpyrifos and Profenfos, respectively after 24 hr., of exposure. In this respect, the toxicity of the insecticide Deltamethrin was 2.58 times more than Methomyl, 2.83 times than Cyhalothrin, 4.98 times than Chlorpyrifos and 3.41 times than Profenfos. On the other hand, the toxicity of Methomyl was 1.93 times, more than Chlorpyrifos 1.37 times than Profenfos and 1.1 times than Cyhalothrin. The toxicity of the tested insecticides against the workers of honeybee after 48 hr., of topical exposure showed LD50 values range from 2.44 to 12.32 μg/bee. The insecticide Deltamethrin was the highest toxic compound where as the Chlorpyrifos was the least toxic one. The other insecticides occupied intermediate degree of toxicity. Deltamethrin toxicity in comparision to the other tested insecticides revealed that it was more toxic than Methomyl by 2.21 times, 2.93 times than Cyhalothrin, 5.01 times than Chlorpyrifos and 3.82 times than Profenfos. The LD50 of Deltamethrin was 1.01 mg/l, 0.1mg/l to Methomyl, 5.21 μg/bee to Cyhalothrin, 7.58 mg/l to Chlorpyrifos and 6.11 mg/l to Profenfos. On the other hand, the corresponding LD90 were 2.31 to Deltamethrin, 8.71 to Methomyl, 9.98 to Cyhalothrin, 13.75 to Chlorpyrifos and 15.73 μg/bee to Profenfos. The tested insecticides could be arranged descendingly as follows: Deltamethrin > Methomyl > Cyhalothrin > Profenfos > Chlorpyrifos. 

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